1. Measuring Radon in Residential Properties
What are the testing strategies
for radon?
Lesson 6
What are the testing strategies for radon?
Connecticut Radon Measurement Training Program 2006

2. EPA goals Help people make decisions about radon reduction that
Are timely
Are simple
Are cost effective
Protect human health
Especially against lung cancer

3. Importance of reliable measurement
Follow EPA protocols for reliable measurement
Helps property owners decide whether to mitigate
May be part of price negotiations in real estate transactions
What should I do to protect my family?
If the mitigation system on our new home will cost $1500,
will the seller reduce the asking price?

4. Review Length of test Short-term test Long-term test 2-90 days
Provides more information about a home’s year-round average radon level
Measures radon levels during brief test period
Often used in real estate transactions
Devices include
Charcoal canisters
Charcoal liquid scintillation detectors
Electret ion chamber devices (short-term E-PERMs)
Continuous monitors
Devices include
Alpha track devices
Electret ion chamber devices (long-term E-PERMs)

5. Measuring Radon in Residential Properties
What are the testing strategies
for radon?
Length of test
Both types of test can provide accurate results
Both types of test usually lead to same decisions about mitigation
Image from University of Illinois Extension, “Take Action on Radon fro Healthy Homes,”
Connecticut Radon Measurement Training Program 2006

6. General testing process (not related to sale of a home)
Step 1
Conduct a short-term test
Step 2
Determine what follow-up strategy is needed
Step 3
Conduct any needed follow-up test
Step 4
Examine results of all tests to determine what to advise the homeowner
Handout 6-1 summarizes this information

7. General testing strategies
Step 1: Assume you have conducted a short-term test
Step 2: Determine what follow-up strategy is needed
Follow-up depends on the first test result
0–under
4 pCi/L
(0–under
0.02 WL)
4–under
10 pCi/L
(0.02–under
0.05 WL)
10 pCi/L and above
(0.05 WL and
above)

8. General testing If the first test result is 0–under 4 pCi/L
You do not have to conduct
a follow-up test now
Advise the owner to test again in the future, especially if
An unused lower level becomes used as a living space
Structural changes are made
Changes in the HVAC system are made

9. General testing If the first test result is 4 pCi/L or more,
conduct a follow-up test
4–under 10 pCi/L
10 pCi/L and above

10. use the long-term results
General testing
If the first test result is
4 pCi/L or more but under 10 pCi/L
Conduct a follow-up
short-term test or long-term test
With another short-term test, average the results of the first and follow-up tests
With a long-term test,
use the long-term results
If the average is under 4 pCi/L, advise the owner to test again in the future
If the average is 4 pCi/L or more,
advise the owner to mitigate
If the result is under 4 pCi/L, advise the owner to test again in the future
If the result is
4 pCi/L or more, advise the owner to mitigate

11. General testing If the first test result is 10 pCi/L or more
Conduct a follow-up
short-term test
Average the results
of the first and follow-up tests
If the average is
under 4 pCi/L,
advise the owner to test again in the future
4 pCi/L or more,
advise the owner to mitigate

12. Example Step 1: Conduct a short-term test
Step 2: Determine follow-up strategy
Test 1 = 5.4 pCi/L
Advise follow-up test
Since result is under 10 pCi/L, either short-term or long-term test OK
Step 3: Conduct follow-up test (short-term)
Step 4: Examine results
Test 2 = 3.8 pCi/L
Average = 4.6 pCi/L
Recommend mitigation
What do you advise?
You are testing for Jeri, who has no plans to sell her Simsbury home
What do you advise?

13. Example What if Jeri had requested a long-term test as follow-up?
Test 2 = 4.0 pCi/L
What do you advise?
Recommend mitigation
You are testing for Jeri, who has no plans to sell her Simsbury home

14. General testing strategies Summary
First test result
0–under
4 pCi/L
4–under
10 pCi/L
and above
No immediate follow-up
Follow-up with short-term or long-term test
Follow-up with short-term test

15. Questions?
About strategies for tests that are not associated with real estate transactions

16. Testing associated with home sales
Why are there potential problems?
Time pressure
Accidental violation of test conditions
Possibility of tampering

17. Testing associated with home sales
Short-term options usually preferred because of time factor
Passive tests
Two simultaneous tests
(two tests at the same time in the same place)
Two sequential tests
(one test right after another in the same place)
Active test
One continuous monitor
Handout 6-2 summarizes this information

18. Real estate option 1 Two simultaneous tests
Conduct two short-term tests at the same time
March 2010 5 6
Begin Tests 1 and 2 7 8
End Tests 1 and 2 9
Use two identical devices and methods
Test in same location
Place two devices 4 inches apart
Run tests for at least 48 hours
Return devices to lab promptly

19. Simultaneous test results
Expect some variation between any two results
Both results are
under 4 pCi/L
Average will be
Report both results and average
Recommend future retesting
Both results are
4 pCi/L or more
Average will be
Report both results and average
Recommend mitigation

20. Simultaneous test results Special situation
One result is under 4 pCi/L and
one result is 4 pCi/L or more
Average may be under, at, or over 4 pCi/L
Consider the difference between the two results

21. Simultaneous test results Special situation
One result is under 4 pCi/L and
one result is 4 pCi/L or more
Consider the difference between the two results
L = lower result H = higher result
Multiply L by 2 and compare with H
If H is less than L x 2, the difference is acceptable
Report results and average
If average is under 4 pCi/L, recommend future retesting
If average is 4 pCi/L or more, recommend mitigation
If H is greater than or equal to L x 2, the difference is too large
Report that the results do not agree
Retest
See handout 6-3

22. Simultaneous test results Special situation example
L = lower result H = higher result
Example 1:
L = H = 4.2
L x 2 = 6.4
H (4.2) is less than L x 2 (6.4),
so the difference is acceptable
Report results and average (3.7)
Example 2:
L = H = 4.6

23. Simultaneous test results Special situation example
L = lower result H = higher result
Example 1:
L = H = 4.2
L x 2 = 6.4
H (4.2) is less than L x 2 (6.4),
so the difference is acceptable
Report results and average (3.7)
Example 2:
L = H = 4.6
L x 2 = 4.4
H (4.6) is greater than L x 2 (4.4),
so the difference is too large
Report disagreement of results (but not results) and retest

24. Simultaneous test results Summary
Expect some difference between the two results
Both results are under 4 pCi/L
One result is under 4 pCi/L and one result is 4 pCi/L or more
Both results are
4 pCi/L or more
Average will be under 4 pCi/L
If the higher result is twice the lower result or more, retest
If the higher result is less than twice the lower, report both results and average
Recommend retesting or mitigation based on average
Average will be
Report both results and average
Recommend future retesting
Report both results and average
Recommend mitigation

25. Real estate option 2 Two sequential tests
Conduct one short-term test after another
First test
Run the first test for at least 48 hours
Return the device to the lab promptly
Immediately after the first test is finished, run a follow-up test
March 2010 5 6
Begin Test 1 7 8 9

26. Real estate option 2 Two sequential tests
Follow-up test
Begin immediately after first test
Use identical device and method
Use same units (pCi/L or WL)
Place device in same location
Run follow-up test for same period as first test
Up to 2 hours difference allowed
Run for at least 48 hours
Return device to lab promptly
March 2010 5 6
Begin Test 1 7 8
End Test 1
Begin Test 2 9

27. Sequential tests Variation in results
Expect some variation between any two results
Radon levels vary from day to day
Moderate variation is acceptable
If variation is large, consider possible causes
Weather
Air pressure
Season
Accidental disturbance of device
Opening of doors or windows
Tampering
Lab error
Moderate variation
Large variation

28. Sequential tests Reporting results
What to report
Report both results
Use average of two test results to determine need for mitigation
When to report
After second test to discourage tampering
Especially if first test result is 4 pCi/L or more

29. Activity See scenario in handout 6-4 What did Hector do wrong?
Hector, an inexperienced inspector, ran two sequential short-term tests in a home for sale in Columbia
See scenario in handout 6-4
What did Hector do wrong?
Revise the scenario so that Hector conducts the tests properly
Consider factors that might explain differences in test results

30. Questions? About simultaneous tests in real estate transactions?
About sequential tests in real estate transactions?

31. Real estate option 3 One continuous test
Use any NEHA- or NRSB-listed continuous monitor or working-level monitor
Use monitor that integrates and records at least every hour

32. Real estate option 3 One continuous test
Run test for at least 48 hours
Requires about 4 hours for conditions to stabilize
Discard data from these 4 hours or correct them
Must have at least 44 continuous (uninterrupted) hours of data for valid average
If you remove any data within that period (for example, if severe weather occurs), results will not be valid

33. Real estate option 3 One continuous test
Results
0–under
4 pCi/L
4 pCi/L or more
Recommend future retesting
Recommend
mitigation

34. Questions?
About continuous testing?

35. Summary Testing period Testing strategies Short-term (2-90 days)
Long-term ( days)
Both provide accurate results
Testing strategies
General testing
Testing associated with real estate transactions

36. Summary General testing steps
Conduct short-term test
Determine what follow-up strategy is needed, depending on first result
0 to under 4 pCi/L
4 to under 10 pCi/L
10 pCi/L or above
Conduct any required follow-up
Examine results to determine what to advise homeowner
When result is under 4 pCi/L, advise future follow-up, especially if major changes are made
When final result is 4 pCi/L or more, advise mitigation

37. Summary Real estate options
Two simultaneous tests using passive devices
Two sequential tests using passive devices
One continuous test

38. Questions?

39. Check your understanding
See handout 6-5